Two years ago, the death of Naoto Watari's parents left him as the sole caretaker for his younger sister Suzushiro "Suzu" Watari and forced him to move in with their aunt. So devoted is he to Suzu that he refuses to join clubs or even hang out with anyone, earning him snide comments and the title of "siscon" at his new school. But as long as Suzu is safe and happy, Naoto doesn't care what everyone else says. However, his sneering classmates may turn out to be the least of his worries. The sudden transfer of a girl named Satsuki Tachibana brings back traumatic memories from his past—a past she had a hand in making so unpleasant. Nasty secrets, unknown to Naoto, begin to surface with her arrival, threatening his new life.

The second season of Yofukashi no Uta. Ko overcomes his confusion about becoming a vampire and decides to "like" Nazuna, while Nazuna resolves to make Ko "fall in love" with her. Without understanding what "love" even is, the two of them spend their nights together in a frenzy. Meanwhile, Detective Uguisu Anko is closing in with her plot to kill vampires, not just Nazuna. A vampire's weakness is "anything they were attached to when they were human" and so they all try to get rid of this weakness before it's too late. But, Nazuna has no memory of her human life. What is Nazuna's hidden past? Why did Anko start killing vampires? And what is the "secret" that Nazuna and Anko share? For Ko, Nazuna, Anko, a fun "late night" doesn't end here... a new "night" begins!

Individuals with Momotarou and Oni blood coursing through their veins maintain a longstanding rivalry. The Oni are careless, rash, and disorderly, while the Momotarou protect the human world from the uncontrollable Oni. Shiki Ichinose is a reckless and irresponsible teenager, aware of his defiance and even proud of his expulsion from school. Despite Shiki's rebellious attitude, his foster father, Tsuyoshi, cares about him deeply. Tsuyoshi's selfless love is soon shown in an explosive incident when a Momotarou barges in looking for Shiki. As a Momotarou himself, Tsuyoshi has been hiding Shiki for years and keeping his Oni origins a secret even from him. As he gives up his life to save Shiki and confesses everything in his dying breath, Shiki's Oni blood awakens for the first time, transforming him into an unruly monster overflowing with rage and a thirst for revenge. Shiki's momentary outburst attracts the attention of Naito Mudano, an Oni teacher at the Rakshasa Academy—an institution for young Oni in need of understanding and perfecting their powers. Before Shiki can avenge his father, he must learn to control his headstrong and impulsive nature and, above all, fight against his own demonic blood.

A squid-like creature, known as a Happian, leaves his home planet with the desire to spread happiness across the universe. He lands on Earth, but quickly finds himself in danger of captivity by its inhabitants. Fortunately, he is found by an unsmiling little girl named Shizuka Kuze, who feeds him and names him Takopii. Feeling indebted, Takopii decides to do everything in his power to bring a smile to her face. The task is easier said than done, however. Shizuka is bullied by her classmates, she does not have a father, and her mother is never home—though the gravity of these issues flies over the naive Takopii's head. Even so, Shizuka does have one source of happiness: her dog Chappy. The connection Shizuka and Chappy share only increases Takopii's desire to make the girl smile. While Takopii's attempts to lift Shizuka's spirits lead to unintended consequences, he is determined to take things into his own tentacles, test his understanding of human beings, and achieve his goal of spreading happiness.